Worries and Watchdogs

Tardy deliveries by subcontractors were among the bigger stumbling
blocks that North American faced in putting the command and service
modules together. Eberhard Rees, an expert in manufacturing management
from Marshall Space Flight Center, was lent to George Low, Apollo
program manager at the Manned Spacecraft Center, to solve fabrication
problems. In the later months of 1967, Rees visited North American and
soon realized that cooperation between the prime contractor and the
subsystem suppliers was not close enough. North American engineers, he
said, should spend more time at the subcontractors' plants while
subsystem assemblies were in critical stages of fabrication. He also
recommended that North American borrow some inspectors from General
Electric to help conduct vendor surveys, specification reviews, and test
failure assessments.3

The subsystem situation came to the attention of George Mueller,
Associate Administrator for Manned Space Flight at Headquarters, when he
visited Downey late in 1967. Mueller on his return to Washington asked
Edgar M. Cortright, his deputy, to go to the major companies, review the
status of hardware, and see if the condition could be improved.4

During January and February 1968, Cortright traveled to nine Apollo
subcontractors. He was impressed with people, equipment, and facilities
but not at all pleased with hardware or schedules. Cortright found that
neither North American nor Grumman knew enough about the status of their
subcontractors' work to be able to forecast deliveries with any degree
of accuracy. The subcontractors, Cortright also said, should be more
aware of the importance of their systems in the total program - they
should not just deliver their products to the dock in Downey or Bethpage
and walk away. He was upset about failures in electronic parts,
especially when he found that the subcontractors were doing their best
to solve their problems by themselves by trial and error. Low asked the
Houston subsystem managers to look into these deficiencies and correct
them.5

Just the barest hint of something wrong with electrical parts, anything
that might be a fire hazard, captured the immediate attention of special
guardian groups. Spacecraft wiring and materials, cabin atmospheres, and
crew safety were the subjects of many meetings. Third-party groups, such
as a Senior Flammability Board, a Materials Selection Review Board, and
a Crew Safety Review Board, were set up to ensure extra safeguards.

Late in 1967, Houston Director Robert Gilruth led a contingent of NASA
officials to a meeting with William Bergen and his staff at North
American* to discuss flammability
problems of the coaxial cable in the command module. Under particular
scrutiny was spacecraft 101, slated for the first manned Apollo mission.
After visually inspecting the vehicle and watching motion picture films
of tests, the group concluded that 23 meters of the coaxial cable might
be flammable. There were several options on what to do about it -
replace it, wrap it with aluminum tape, partially wrap it to provide
fire breaks, or leave it alone. Since other spacecraft wiring and
electrical equipment might be damaged during replacement, even with
extreme care, they decided it would be safer to fly 101 essentially as
it was, with the exception of one bundle that would be wrapped.**6

No sooner had one NASA group acted than another demanded a defense of
what had been done. Aleck C. Bond, speaking for the Houston Materials
Selection Review Board, queried Low about the cable. Low pointed out
that the decision had been made at the highest Apollo management level
of both North American and NASA. He also reminded Bond that, in the NASA
system of checks and balances, the board did not approve changes. It
only recommended approval or disapproval. Low then required that all
deviations be assessed by his Configuration Control Board and forwarded
to Apollo Program Manager Phillips in Washington for final review.7

Most of the Flammability Board's attention focused on cabin atmosphere
at the launch site, which also affected materials selection. Established
in September 1967, with Gilruth as chairman, the board directed several
series of tests under a variety of atmospheric mixtures and pressures
for pad operations. Thirty-eight tests had been completed by 7 January
1968. In the middle of the month, a second series began, using
principally a 60-per-cent-oxygen and 40-percent-nitrogen mix (normal
atmosphere is 21 percent oxygen and 78 percent nitrogen, with traces of
other gases). This series ended on 25 January, and evaluations began.

Max Faget, whose engineers in Houston ran many tests for Gilruth's
board, said they used pure oxygen at a higher than normal pressure on
the pad to check for air leaks from the cabin. After the Apollo 204
fire, everyone was aware that this was dangerous. They then ran pure
oxygen tests at one-third the pressure (which simulated orbital
conditions). With cabin fans off and no other means of spreading the
flames, they found that fire would not propagate as rapidly in space. So
Faget's group agreed that if they could make the spacecraft safe on the
ground, it would be safe during flight.

But there was no way to put 100-percent-fireproof materials in the
spacecraft, especially in the electrical system. Many persons began
campaigning for a two-gas atmosphere, with a higher concentration of
nitrogen than oxygen. Use of this mixture would have required completely
rebuilding the spacecraft to withstand the pressures of a sea-level
atmosphere. The command module could withstand only about half that
pressure in space, and the lunar module even less. Moreover, a mixed
atmosphere in space would complicate the environmental system - Faget
said the system "would get confused and would put too much nitrogen
in the cabin, a very insidious thing because there was no way to detect
[it]." The astronauts would just get sleepy - and die. Another
complication was that a switch back and forth from the two-gas system in
the cabin and the 100 percent oxygen in the hoses connected to the suits
might give the crew aeroembolism, or the bends.

So the question was twofold: How much nitrogen was needed on the pad to
prevent fire? And how much oxygen was needed during launch while the
cabin pressure relief valve was venting? Tests revealed that a
60-percent-oxygen and 40-percent-nitrogen mixture at a pressure of 11.2
newtons per square centimeter (16.2 pounds per square inch) on the pad
would result in 1.4 newtons (2 psi) in orbit after venting, which would
give a partial pressure of oxygen compatible with the oxygen atmosphere
and pressure in the suits. The cabin pressure would be lower at first,
but the mixture would be breathable and it would sustain life. In fact,
by the time the craft reached orbit, Faget said, the cabin mixture would
actually be about 80 percent oxygen. And there was a bonus in this
arrangement beyond the safety factor: no structural changes were needed
in the spacecraft to accommodate this combination of oxygen and
nitrogen.8

Low promised Phillips a decision on the prelaunch atmosphere in time for
spacecraft 101's Design Certification Review. A third set of tests,
using boilerplate 1224, confirmed conclusions drawn from the second
series. Gilruth's Flammability Board met on 4 March and recommended the
60/40 mixture for the launch pad. On 7 March, Mueller's Certification
Board accepted this recommendation. In April, NASA's medical group,
expressed "enthusiastic approval of the . . . decision to adopt the
60/40 atmosphere."9

For a while there was a good deal of discussion about the lunar module
cabin atmosphere on the launch pad. Low recommended 100 percent oxygen
for the LM, since there was no crew and little electrical power in the
vehicle during launch. Moreover, the spacecraft-lunar module adapter,
which held the lander, was filled with nitrogen, reducing flammability
hazards to almost nothing. This procedure, Low pointed out, would save
some of the lander's oxygen supply, as well as minimizing crew
procedures in changing the mixture to pure oxygen after launch.
Marshall, however, objected, because any oxygen escaping from the lander
during the launch phase might come in contact with hydrogen leaking from
the S-IVB into the adapter and start a fire. Houston conceded that the
advantages of launching the lunar module with pure oxygen had to give
way to Huntsville's concerns; the atmosphere in the lander's cabin at
launch would not exceed 20 percent oxygen.10

Another set of watchdogs, formed to consider manned operation of the
machines, was the Apollo Crew Safety Review Board. Since Gilruth's team
mas investigating "spacecraft fire safety and air-on-the-pad,"
the new group, at its first meeting in March 1968, began looking for
problems that might be missed by other specialized committees. Led by
John Hodge in Houston, the board concentrated on operations - all
activities from the time the crew boarded the spacecraft through the
launch phase - searching for weak links and hazards. One big worry that
had to be faced was the possibility of a Saturn engine shutting down on
the pad or during the launch trajectory.11

The Hodge Board was not the only group worrying about a Saturn V engine
malfunction. Major General David M. Jones, Commander of the Eastern Test
Range, reminded KSC Director Kurt Debus that the launch vehicle would
remain over the Cape area for almost two minutes. Jones wanted the
vehicle to move out over water as quickly as possible. Debus told
Phillips what Jones had asked, adding that the launch azimuth should not
be tampered with, since a wide range would be needed for a lunar launch.
Phillips turned to Marshall for an answer, and the launch vehicle
engineers modified the pitch program so the vehicle would head eastward
sooner after launch than originally planned.12

Although the Saturn V may have been the key vehicle for escaping the
earth's gravity for the lunar trip, the keystone in the arch leading to
the surface of the moon itself was the lunar module. At least, that was
the way the Flight Operations Division in Houston viewed LM-1's upcoming
trial in earth orbit.13 And the path to
the launch pad for that craft had been a long and arduous one.

* On 22 September 1967, North
American Aviation and the Rockwell-Standard Corporation had merged into
a single company, North American Rockwell Corporation, which was then
divided into two major elements - the Commercial Products Group and the
Aerospace and Systems Group. For consistency and brevity, this history
will refer to the latter as "North American."

** Since they were not as far down
the production line as 101, spacecraft 103 through 106 would have their
coaxial cables removed and wrapped, which should not take longer than
five days. Later spacecraft would be fitted with coaxial cables that met
nonmetallic materials guidelines.